Steam iron



Dec. 13, 1955 c. H. SPARKLIN 2,726,466

STEAM IRON Filed April 19, 1952 2 Sheets-Sheet l O; \h R g m- & w grj Dec. 13, 1955 c. H. SPARKLIN 2,726,466

STEAM IRON Filed April 19, 1952 2 Sheets-Sheet 2 W I W" United States Patent STEAM IRON Charles H. Sparklin, Chicago, lll., assignor to Birtman Electric Company, a corporation of Illinois Application April 19, 1952, Serial No. 283,161

1 Claim. (Cl. 38-77) This invention relates to a steam iron and particularly to the sole plate thereof including the steam generating chamber, steam outlet chamber and communicating passage.

In electric steam irons, a steam generating chamber is provided to receive heat from the heating elements so as to convert water in this chamber into steam. This steam is then conducted to a steam outlet chamber or a portion of the generating chamber is used as an outlet chamber in order that this steam may be vented through the sole plate to the bottom thereof for contact with the fabric being ironed.

In most prior steam irons, considerable difiiculty has been encountered in providing effective heat transfer to prevent the passage of water from the steam generating chamber onto the fabric. This problem has been particularly acute when the steam demand is high such as when relatively heavy fabrics are ironed and the valve control mechanism is opened wide. Under these conditions the steam generating portion of the iron often becomes overloaded sO that not all of the water is converted into steam before it leaves the iron.

In the steam iron of this invention a steam generating chamber, a steam outlet chamber, and a connecting passage are so constructed that all the water fed into the steam generating chamber, even under the most severe operating conditions, is converted into steam before the steam leaves the exit passage from the iron. Furthermore, the heating and steam generating portion of the iron are so designed that a minimum of space is used. Thus the water storage capacity of the iron is large in relation to the over-all size of the iron.

The invention will be described as related to the embodiments shown in the accompanying drawings. Of the drawings:

Figure l is a vertical section taken through a steam iron constructed according to this invention with this section being substantially along the line 1-1 of Figure 4;

Figure 2 is an enlarged fragmentary detail view of a portion of Figure 1 showing the valve structure and associated parts;

Figure 3 is a plan view of the portion of the iron beneath the water reservoir and the enclosing shell; and

Figure 4 is a horizontal sectional view of the iron taken substantially along the line 44 of Figure 1.

The steam iron shown in the accompanying drawings is provided with a sole plate and enclosing shell 11 thereover and a handle 12. Within the shell 11 there is provided a water reservoir 13 attached to the shell and to the sole plate structure. At the front of this reservoir there is provided an upwardly extending hollow member 14 located within the front portion of the handle and provided with a front opening 14a through which water may be poured to fill the reservoir 13. Because of the spaced relationship of this opening 14a to the reservoir 13, no plug is required for this opening unless such is desired.

' The sole plate 10 is provided with converging heating elements 44 underlying cover plates 15 arranged substanice tially in a V shape. This sole plate is preferably generally of the type described and claimed in the Charles H. Sparklin and Philip J. More copending application Serial No. 68,588 filed December 31, 1948. Within the sole plate and between the heating elements 44 there are provided a steam generating chamber 16, a steam outlet chamber 17, and a connecting labyrinth 18 therebetween.

An important feature of the sole plate is its extremely low height which is only a fraction of the maximum width of the plate. This low height permits increased water storage capacity without excessively increasing the overall height of the body portion of the iron in that it permits the use of a larger water reservoir than that ordinarily possible. In the preferred iron, the height of the chambers 16 and 17 and the passage 18 is preferably not greater than about 15% of the maximum width of the sole plate. In the embodiment shown, this height is somewhat less than 10% of the maximum width of the sole plate.

As is shown in Figures 1 and 4 the steam chambers 16 and 17 and the steam passage 18 therebetween are defined by Walls including the walls 10a, 10b, 10c, 10d, 10e, 10 and 10g which are open at the top when the sole plate structure 10 is disassembled but are normally closed by an over-all closure plate 19 which is attached to the sole plate proper by means of screws 20 or the like.

As can be seen in Figure 4, wall 10a separates the steam generating chamber from the steam outlet chamber 17 although these chambers are closely adjacent to each other and near the front of the iron. The steam passage 18 leads from the steam generating chamber 16 toward the rear of the iron and then progresses back and forth in the space between the heating elements 44 toward the front of the iron and terminates in the steam outlet chamber 17. From this outlet chamber 17, the steam flows through one or more exit orifices 10h to the bottom of the sole plate which is provided with radiating grooves 10j to aid in distributing the steam.

The steam passage 18 is made extremely long for the amount of space available and is preferably at least as long as the over-all length of the sole'plate. In the embodiment shown, it is considerably longer than the over-all length of this sole plate. By providing such a long steam passage between the generating chamber 16 and the steam outlet chamber 17, any water carried by the flowing steam from the chamber 16 has ample time to be converted into steam before it reaches the orifice 10h. The conversion of all water into steam is further aided by making numerous sharp turns, most of which are about in the steam passage. This conversion of .all water into steam is further ensured by making the long dimension of the cross section of the passage vertical as shown in Figure 1. These relatively long walls 10f, therefore, are easily heated as they form an integral part of the sole plate and any droplet of water carried by the steam is projected around a curve at such a speed that it strikes one of these heated walls and flattens out thereagainst so that maximum heat transfer is achieved. Conversion of substantially all of the water into steam is further ensured by providing wide wall 10a at the exit of the steam passage 18 into the outlet chamber 17. This wall is preferably wider than its height and has its top portion below the bottom surface of the closure plate 19 but considerably above the bottom of the steam passage 18. Thus, any droplet of water that might exist at the exit of the steam passage must be propelled over the wall 10e before it can get into the outlet chamber 17. In order to do this, the droplet must, of course, pass across the relatively wide top surface of this wall 10:: where it again will receive heat to convert any such droplet into steam. In actual practice, with the iron operating at normal temperatures,

no water has ever been observed at the exit of the outlet passage h.

In order to control the fiow of water from the reservoir 13 to the steam generating chamber 16, there is provided a valve 21 communicating between the interior of the reservoir and the chamber 16. As is shown in Figures 1 and 2, this valve preferably has a threaded lower end 210 of smaller diameter than the upper portion of the valve and that is screwed into an opening 19a in the closure plate 19. At the top of this closure plate there is provided a nut 22 with an annular portion 13a of the wall of the reservoir positioned between the larger upper part 21b of the valve and the nut 22. With this construction, the valve 21 not only provides a controllable water flow from the reservoir 13 to the steam generating chamber 16 but also serves to attach the front part of the reservoir to the sole plate structure.

The interior of the valve 21 is provided with an extended cylindrical passageway 21c communicating by means of a plurality, preferably four, side passages 21d with the interior of the reservoir 13. The bottom of the passageway 21 is defined by an inwardly and downwardly sloped flange 23 having a relatively small opening 23!: therein.

The valve closure member, arranged to operate against the inclined bottom flange 23, comprises a hollow body or tube 24. As can be seen most clearly in Figure 2, the bottom part of this tube is spaced from the inner surface of the passageway 21c while the part 24b immediately above this part 24a and above the side passages 21d substantially fills this passageway 21c so that it acts as a piston therein. The portion 240 of the tube 24 above the part 24b is enlarged still further as it is always beyond the valve 21.

Extending into the top part 240 of thehollow body or tube 24 is an elongated member or rod 25 that is provided with an annular collar 25a spaced from the top of the tube 24 so that a helical spring 26 positioned around the rod 25 will bear upwardly against the collar 25a and downwardly against the top of the tube 24.

The top end of the tube 25 is threaded into a closure plug 27 closing the top of the hollow member 14. The extended end of the rod 25 is provided with a knob 28 having a downwardly projecting pin 29 adapted to be guided in an arcuate groove 27a upon rotation of the knob 28.

The lower part of the rod 25 is provided with a pair of outwardly projecting studs 25b positioned in elongated slots 24c in the wall of the tube 24. Projecting from the bottom end of the rod 25 is a pin-like member 33 located substantially centrally within the hollow body 24 and longitudinally thereof with the bottom end 30a of this member being blunt. When the member 30 is in its lowermost position with the studs 25]; at the bottoms of the slots 240, this end 30a will extend slightly below the water opening 23a and the member 30 will substantially fill this opening.

With the structure as described, the spring 26 always urges the tube 24 downwardly so that when the knob 28 is rotated, the bottom tapered end 24d of the tube will seat against the tapered flange 23 and close the water passage at the earliest possible moment. This water passage is defined by the side passages 21d, the central passage 21c, and the lower relatively small opening 23a.

When the parts are in the position shown in Figures 1 and 2, the bottom end 24d is in its initial contact with the flange 23 to stop the flow of water. Further rotation of the knob 28 in closing the valve rotates the tube 24 by means of the cooperation between the side slots 24c and the studs 25b. This further rotation with the spring 26 holding this bottom part 24d against the flange serves to dislodge any sediment, scale or other obstructions that might be on the valve seat and that might interfere with proper closing of the valve. This continued rotation also causes the rod member 26 and the attached pin-like member 30 to continue their downward travel so that the lower end 3011 will project through the passage 23a. This will dislodge any obstructions such as sediment and scale that might be present by a shearing and scraping action. As can be seen from this description, both the final closing movement and the initial opening movement of the valve closure dislodges obstructions that may be present in the water passage. Continued opening movement of the valve caused by the rotation of the knob 28 serves to withdraw both the lower end 24d of the tube 24 and the lower end 30:: of the pin like member 30 away from the flange 23 defining the valve seat and its opening 23a so that water may flow into the steam chamber 16.

With the valve structure as explained above, the flow of water from the reservoir 13 into the steam generating chamber 16 can be very carefully controlled so that only the desired amounts of water are supplied, The larger portion of this water is almost instantaneously flashed into steam as soon as it hits the bottom of the steam generating chamber 16. The steam then flows at a rapid rate through the steam passage 18 around the many corners and finally over the bafile 10c into the steam outlet chamber 17. From this outlet chmaber, the steam flows through the orifice 1011 and the radiating passages 161' onto the cloth being ironed.

The temperature at which the iron operates may be regulated by a thermostat that is adjustable to any desired temperature setting within the operating range of the iron. Any suitable adjusting mechanism desired may be used. In the embodiment shown, the adjusting mechanism comprises a tubular shell 31 extending through the reservoir 13 and having a substantially square or rectangular inner bore 31a. Within this bore 31a there is positioned a substantially vertically slidable operating member 32 of the same shape. This member 32 is provided with a substantially circular threaded recess threadingly receiving the threaded lower end 33a of a rotatable member 33. This member 33 is rotatably held in a closure 34 ad.- jacent to the top end of the tubular shell 31 and normally closing this end. The rotatable member 33 is provided with an upper end portion 33!; extending above the shield portion 12a of the handle 12 and adapted to receive a button or the like for rotating the member 33.

The lower end 32a of the slidable member 32 bears against a spring arm 35 which carries a contact button 36 at its outer end. This contact button bears against another contact button 37 on a second spring arm 38. The springiness of the arms 35 and 38 hold the buttons 36 and 37 in contact and permits them to move up or down as a unit with the buttons in contact until they are forcibly separated. Thus, the position of the slidable member 32 determines the position of the spring arms 35 and 38. This relative position determines the operating temperature of the iron.

In order to separate the arms 35 and 38 and thus the contact buttons 36 and 37 when the temperature exceeds the predetermined setting controlled by the position of these arms, there is provided a bimetal strip 39 housed in a well 40 within the sole plate 10 and between a heating element 44 and the steam passage 18 Flexing of this bimetal upwardly under the influence of increasing temperature causes a post 41 on the free end thereof to force the spring arm 38 upwardly and separate the contact buttons 36 and 37 when the temperature exceeds the predetermined value that is depended upon the relative positions of the spring arms 35 and 38. With the above construction, the temperature is easily regulated by rotating the upper end 33b of the member 33. When this upper end is rotated, the engagement of the lower end 33a with the slidable member 32 causes this member to slide upwardly or downwardly within the bore 31a of the shell 31 to position the spring arms 35 and 38 to a position corresponding to the desired temperature. This temperature will then be maintained by flexing of the bimetal 39 which will cause the buttons 36 and 37 to separate when the temperature exceeds this predetermined value and will cause the buttons to again contact when the temperature falls below this value. The spring arms 35 and 38 are in the electrical circuit that includes resistance strip 44 so that the flow of electricity to this strip is immediately stopped when the buttons 36 and 37 are separated. By locating the bimetal 39 within the well 40 in the sole plate, good heat transfer is obtained. Similarly, by locating this strip 39 adjacent to the steam passage 18 at a point that is near the entrance of this steam passage any water flowing through the steam passage will tend to cool that portion of the sole plate containing the bimetal strip and ensure that a sufficiently high temperature is maintained to convert this water into steam.

As is shown in Figure 3, the closure and temperature storage plate 19 that forms the top wall of the various steam chambers and the steam passage and which is held in place by the screws 20 is cut away at 19a so that the bimetal post 41 will be free to operate.

Having described my invention as related to the embodiments shown in the drawings, it is my intention that the invention be not limited by any of the details of description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the accompanying claim.

I claim:

in an electric steam iron, a sole plate including a heat ing element arranged in a forwardly converging substantially V-shape with the apex of the element located adjacent to the toe of the sole plate, a steam generating chamber adjacent to said apex, a steam outlet chamber adjacent to said apex and separate from said generating chamber, the sole plate having an opening leading from said outlet chamber through the bottom of the sole plate, and a plurality of transverse walls forming a steam passageway extending rearwardly from said generating chamber to an area adjacent to the heel of the sole plate and then forwardly of the heel to said steam outlet chamber, a portion of said passageway between the rear diverging ends of said heating element being labyrinthian, the heating element, steam generating chamber, steam outlet chamber and passageway-forming transverse walls being substantially aligned in a plane substantially parallel to the bottom surface of the sole plate, said chambers and passageway-forming transverse walls being located substantially entirely within the area defined by said heating element.

References Cited in the file of this patent UNITED STATES PATENTS 2,016,961 Dowinsky Oct. 8, 1935 2,179,259 Jones Nov. 7, 1939 2,279,215 Theilgaard Apr. 7, 1942 2,485,664 Scott Oct. 25, 1949 2,499,184 Finlayson Feb. 28, 1950 2,500,185 Kassab Mar. 14, 1950 2,553,274 Pohl May 15, 1951 2,573,174 Bate Oct. 30, 1951 FOREIGN PATENTS 535,294 Great Britain Apr. 4, 1941 595,515 Germany Apr. 14, 1934 

